FXUS66 KLOX 221151
AFDLOX
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
300 AM PST FRI NOV 22 2002

COOLING WILL BE THE MAIN STORY ACROSS THE FCST AREA FOR THE NEXT FEW 
DAYS. OFSHR GRADS WERE WEAKENING RATHER QUICKLY ACRS THE AREA THIS
MORNING. AN AREA OF STRATUS WAS ALEADY BEGINNING TO PUSH INTO IMDT
CSTL SXNS OF SLO AND WRN SBA COUNTIES...AND WAS SURGING THRU THE 
SANTA BARBARA CHANNEL INTO CSTL SXNS OF SRN SBA AND VTU COUNTIES. 
THERE IS A CHANCE THAT LOW CLDS AND FOG MAY EVEN SNEAK INTO IMDT
CSTL SXNS OF L.A. CNTY BY DAYBREAK. MARINE INVERSION WAS NEARLY
SURFACE BASED...AND DENSE FOG WL LIKELY ACCOMPANY THE STRATUS
THIS MORNING. WL ISSUE DENSE FOG ADVISORIES FOR CSTL ZONES THIS 
MORNING...AT LEAST FROM VTU COUNTY NWD...ALTHOUGH THE DENSE FOG WL
PROBABLY REMAIN CONFINED TO LOCATIONS WITHIN A FEW MILES OF THE IMDT
CSTL. WITH THE RETURN TO ONSHR FLOW...XPCT DRAMATIC COOLING ACRS THE
CSTL PLAIN TODAY...WITH MOST LOCATIONS 10 TO 15 DEGS COOLER THAN ON
THU...AND COOLING OF UP TO 20 DEGS IN A FEW LOCATIONS. THE RETURN TO
ONSHR GRADS AND COOLING AT 950 MB SHOULD LEAD TO SEVERAL DEGS OF 
COOLING IN THE VLYS TODAY...AND ALTHOUGH CERTAINLY NOTICEABLE...COOLING
IN THE VLYS WL PROBABLY NOT BE QUITE AS DRAMATIC AS ON THE CSTL PLAIN. 
XPCT MUCH LESS IN THE WAY OF COOLING IN THE MTNS AND DSRTS TODAY.

AN UPR TROUGH WL MOVE INTO THE W CST TONIGHT AND SAT...WHICH SHOULD
HELP TO DEEPEN THE MARINE LAYER SOMEWHAT. ONSHR FLOW WL INCREASE...
SO XPCT LOW CLOUDS TO BECOME MORE WDSPRD ACRS THE CSTL PLAIN. STILL
THINK THAT INVERSION WILL REMAIN LOW ENOUGH TO KEEP LOW CLOUDS 
OUT OF THE VLYS FOR THE MOST PART...AND TO ALLOW FOR SOME LCLLY 
DENSE FOG AGAIN ACRS THE CSTL PLAIN. MORE WDSPRD CLOUD COVER AND 
INCREASED (ALTHGOUH STILL RATHER WK) ONSHR GRADS SHOULD LEAD TO 
ADDITIONAL COOLING ACRS THE CSTL PLAIN...MOST SIGNIFICANT IN INLAND
AREAS. WITH THE DEEPENING OF THE MARINE LAYER AND ADDITIONAL COOLING
AT 950 MB...VLYS SHOULD COOL SIGNIFICANTLY ON SAT...EVEN IF LOW CLOUDS
DO NOT MAKE IT INTO THE VLYS. FALLING THICKNESSES AND COOLING AT 850 MB
WL HELP PRODUCE SEVERAL DEGS OF COOLING IN THE MTSN AND DSRTS ON SAT.

AS THE UPR TROUGH MOVES E OF THE AREA LATE SAT INTO EARLY SUN...WEAK
SHORT WAVE RIDGING WL TRY TO BUILD BRIEFLY INTO THE W CST. WITH LOW
LVL NLY FLOW ACRS THE AREA...THIS COULD HELP TO DECREASE THE LOW 
CLOUD COVERAGE SAT NIGHT AND SUN...AND IT IS CONCEIVABLE THERE 
COULD EVEN BE A BIT OF WARMING ON SUNDAY. HOWEVER...THE 06Z ETA 
SHOWS A WEAK EDDY CRCLN...AND SUGGESTS THAT LOW CLOUDS COULD 
SPREAD INTO THE VLYS OF AT LEAST L.A. COUNTY SAT NIGHT/SUN MORNING. 
WITH THIS UNCERTAINTY...WL LEAVE THE FCST AS IS...CALLING FOR SOME
INCREASE IN LOW CLOUD COVERAGE AND ADDITONAL COOLING ON SUNDAY.

BEYOND SUNDAY...THERE IS A GREAT DEAL OF DISAGREEMENT WITH THE
MODELS...AND EACH SOLUTION WOULD PRODUCE VERY DIFFERENT WEATHER
ACRS THE FCST AREA. THE MAIN DIFFERENCE STEMS FROM THE AMOUNT OF
ENERGY EACH MODEL DROPS SWD INTO CA. THE GFS SHOWS A RATHER
STG UPR TROUGH CLOSING OFF AS IT MOVES ACRS CA INTO NEVADA
SUN NIGHT AND MON...THEN ADDITIONAL ENERGY DROPPING SWWD THRU
THE ROCKIES...STRENGTHENING THE UPR LOW AND PULLING IT SWWD 
ACRS THE FCST AREA TUE INTO WED. THE GFS SOLN IS SOEMWHAT OF
AN OUTLIER...WITH NONE OF THE OTHER MODELS DROPPING NEARLY 
AS MUCH ENERGY SWD INTO CA. AT THIS TIME...IT APPEARS THAT
NEXT WEEK WL BE A RATHER COOL WEEK ACRS THE FCST AREA. IF THE
GFS VERIFIES...SOME SHOWER ACTIVITY IS A POSSIBILITY ACRS
PORTIONS OF THE FCST AREA NEXT WEEK...BUT FOR NOW...WL
JUST GO WITH THE IDEA OF A COOLER AND BREEZY WEEK...WITH
SOMEWHAT MORE IN THE WAY OF CLOUD COVER.

LAX 000. BRUNO.

.LOX...DENSE FOG ADVISORY (SEE LAXNPWLOX).